Date: Mon, 11 Dec 2017 15:55:55 +0300
From: Ildus Kurbangaliev <i.kurbangaliev@postgrespro.ru>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Tomas Vondra <tomas.vondra@2ndquadrant.com>, Alvaro Herrera
 <alvherre@2ndquadrant.com>, =?UTF-8?B?0JXQstCz0LXQvdC40Lkg0KjQuNGI0Lo=?=
 =?UTF-8?B?0LjQvQ==?= <itparanoia@gmail.com>, Andres Freund
 <andres@anarazel.de>, Oleg Bartunov <obartunov@gmail.com>, Craig Ringer
 <craig@2ndquadrant.com>, Peter Eisentraut
 <peter.eisentraut@2ndquadrant.com>, PostgreSQL Hackers
 <pgsql-hackers@postgresql.org>
Subject: Re: [HACKERS] Custom compression methods
Message-ID: <20171211155555.05ddd2fc@postgrespro.ru>
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On Fri, 8 Dec 2017 15:12:42 -0500
Robert Haas <robertmhaas@gmail.com> wrote:

> 
> Maybe a better idea is ALTER COLUMN SET COMPRESSION x1, x2, x3 ...
> meaning that x1 is the default for new tuples but x2, x3, etc. are
> still allowed if present.  If you issue a command that only adds
> things to the list, no table rewrite happens, but if you remove
> anything, then it does.
> 

I like this idea, but maybe it should be something like ALTER COLUMN
SET COMPRESSION x1 [ PRESERVE x2, x3 ]? 'PRESERVE' is already used in
syntax and this syntax will show better which one is current and which
ones should be kept.

-- 
----
Regards,
Ildus Kurbangaliev